The invention relates to a method of deaerating water and, more particularly, to an energy-efficient method of deaerating water.
In the power, food, chemical and other processing industries, large quantities of deaerated water frequently are required to achieve product purity, for corrosion protection or for other processing reasons. Not infrequently, the deaerated water is stored in relatively large storage tanks having capacities ranging up to the hundreds of thousands of gallons. Although the water may meet specification requirements when originally introduced into the storage tanks and the tanks may be provided with air exclusion devices such as rubber diaphragms or floating roofs, nevertheless air may leak into the tanks if, e.g., the air exclusion devices have deteriorated over time.
To keep large quantities of deaerated water sufficiently pure, supplementary deaeration systems are often employed to assure that the water meets the process specification. A well known system employs vacuum deaeration to maintain the water specification wherein the water is introduced into a deaeration column operating near the vapor pressure of the water being deaerated. A water sealed mechanical vacuum pump is generally employed to draw the vacuum on the deaeration column by evacuating the air (together with dissolved and entrained water) from the water flowing through the column. The deaerated water may be recirculated back to the supply tanks or may be introduced into the process.
While such deaeration systems are generally effective, the art continues to search for more efficient processing improvements.